1. Field of the Invention
The present invention relates to steering and braking systems, and more particularly to, an absolute angular sensor of a steering system for vehicles.
2. Description of the Conventional Art
FIG. 1 and FIG. 2 show the construction of a prior art steering sensor and a prior art rotator disc. In FIG. 1, and FIG. 2, a conventional steering sensor usually includes a photo interrupt part composed of a photo diode 1 and a photo transistor 2, a signal processor part 3 for processing signals input from the photo interrupt part, and a rotator disc 4 having a plurality of holes 5.
In the conventional steering sensor, the rotator disc 4 rotates in the photo interrupt. If the position of the photo diode 1 coincides with that of the holes 5 during the rotator disc""s rotation in the photo interrupt, light from the photo diode 1 passes through the holes 5 of the rotator disc 4 to the photo transistor 2. According to the light input to the photo transistor 2, the signal processor part 3 recognizes a signal (e.g., high level).
On the other hand, if the photo diode 1 does not coincide with the holes 5 of the rotator disc, then the light from the photo diode 1 can not pass through the holes 5 nor reach the photo transistor 2. In this case, the signal processor part 3 recognizes a signal (e.g., low level). Therefore, the degree of rotation of a steering shaft is confirmed by continuous numbers of the signals.
However, the conventional steering sensor has a disadvantage in that the steering sensor senses only relative angle and relative angular velocity, so that it is impossible to sense an absolute position of the steering shaft. According to the conventional steering sensor, it is impossible to check as to whether the steering shaft is positioned at a first turn angle or a second turn angle, since the steering shaft may turn totally 3.5 rounds, that is, 1260 angle degrees.
Therefore, it is required to develop an absolute angular sensor for sensing the absolute position of the steering shaft in a steering system.
The present invention is derived to resolve the disadvantages of the conventional techniques and it is an object of the present invention to provide an absolute angular sensor of a steering system for vehicles, in which an absolute angle of a current steering shaft position may be sensed by converting an absolute rotation displacement of the steering shaft into a linear displacement by means of a linear variable displacement transducer.
In order to achieve the above objects of the present invention, in the steering and braking systems, a rotator disc is mounted under a steering shaft so that a rotation of the rotator disc in response to rotation of the steering shaft is converted into a linear displacement by the linear variable displacement transducer, thereby sensing an absolute position and an absolute angle of the handle accurately.